Ginny and her husband John McGowan, Abbey’s stepfather, became concerned when Abbey and her older brother Austin were late to meet the couple in the lobby of the Iberostar Paraiso Resort in Playa del Carmen.

“Probably the most excited person was Abbey,” Ginny said. “We just sat on chairs at the side of the pool, and we’re like, we’re going to go up and get ready for dinner. You guys need to meet us in the lobby at 7:30.”

Austin and Abbey stayed by the pool, where they were served shots.

“We swam around for a little bit and decided let’s celebrate with a drink,” Austin told ABC News. “So we go up to the bar, and another group that was already there start talking…we didn’t know them. The bartender pours out a line of shots, and I take one, and everyone else does. And the last thing I remember was like we are right now, sitting here talking, and lights went out. And I woke up in the ambulance.”

Austin doesn’t remember how many shots he had, but authorities said that the siblings’ blood alcohol levels were both .25, three times the legal limit in Wisconsin, where the family is from.

“How, if we’re in a group of people, do two people at the same exact time just pass out in the pool and no one sees it?” Austin said.

The McGowans wonder if bootleg alcohol is to blame for their daughter’s sudden death.

Other families who have vacationed at all-inclusive Mexican resorts have reported similar incidents, including sudden blackouts after consuming small amounts of alcohol, calling into question the purity of drinks served at certain resorts.

The Iberostar resort where the death occurred denies serving tainted alcohol.

“We only purchase sealed bottles that satisfy all standards required by the designated regulatory authorities…We are deeply saddened by this incident and reiterate our deepest sympathies and condolences to the family,” it said in a statement to the Milwaukee Journal Sentinel.

The family has hired an attorney and plans to sue the resort.

Ginny regrets that her daughter’s life ended so abruptly.

“She was on the right path, a good path for her,” she said. “And she was happy.”